title: Zero effect of multiple dosage of olive leaf supplements on urinary biomarkers of oxidative stress in healthy humans.
abstract: OBJECTIVE
  We determined the effect of dietary supplementation with an olive leaf capsule or liquid extract on oxidative status of young and healthy male and female subjects.
  
  
  METHODS
  This was a single-center, randomized, single-blinded, prospective pilot comparison of the effect of dietary supplementation with olive leaf extracts. Healthy young adult male and female subjects (n = 45) were randomized into three groups and received daily doses of control, capsule, or liquid extract of olive leaf. Urinary F(2 alpha)-isoprostane, 8-hydroxy-2'-deoxyguanosine, and Folin-Ciocalteu total reducing power were measured to assess the impact of supplementation.
  
  
  RESULTS
  Baseline values (mean +/- standard deviation) of the biomarkers were 0.24 +/- 0.13 microg, 9.16 +/- 2.94 microg, and 424.9 +/- 121.4 mg of gallic acid equivalents per gram of creatinine, respectively, for the control group. Using these markers, supplementation with liquid or capsule did not alter oxidative status compared with the control group. Possible reasons for the lack of an observed correlation are presented.
  
  
  CONCLUSIONS
  Dietary supplementation with olive leaf extract did not alter the oxidative status of healthy young adults.
authors.affiliation: Charles Sturt University, School of Wine and Food Sciences, Wagga Wagga, New South Wales, Australia.
authors.forename: Megan
authors.initials: M
authors.lastname: Kendall
authors.forename: Marijka
authors.initials: M
authors.lastname: Batterham
authors.forename: Hassan
authors.initials: H
authors.lastname: Obied
authors.forename: Paul D
authors.initials: PD
authors.lastname: Prenzler
authors.forename: Danielle
authors.initials: D
authors.lastname: Ryan
authors.forename: Kevin
authors.initials: K
authors.lastname: Robards
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000704:Analysis of Variance; D000975:Antioxidants / Q000494:pharmacology*; D015415:Biomarkers / Q000652:urine; D003404:Creatinine / Q000652:urine; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000652:urine; D019587:Dietary Supplements; D015237:Dinoprost / Q000031:analogs & derivatives / Q000652:urine; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D031658:Olea / Q000737:chemistry*; D018384:Oxidative Stress / Q000187:drug effects*; D010865:Pilot Projects; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D011446:Prospective Studies; D016037:Single-Blind Method; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D010936:Plant Extracts; C075750:8-epi-prostaglandin F2alpha; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003404:Creatinine; D015237:Dinoprost; D003849:Deoxyguanosine